Processes

22 pages, 7124 KiB

Open AccessEditor’s ChoiceArticle

Development of a Moving Bed Reactor for Thermochemical Heat Storage Based on Granulated Ca(OH)₂

by Aldo Cosquillo Mejia, Sandra Afflerbach, Marc Linder and Matthias Schmidt

Processes 2022, 10(9), 1680; https://doi.org/10.3390/pr10091680 - 24 Aug 2022

Cited by 7 | Viewed by 2810

Calcium hydroxide is promising for thermal energy storage due to its low cost and high energy density. Nevertheless, the powdered material is cohesive and has low thermal conductivity which is a major challenge for the operation of moving bed reactors. One approach to [...] Read more.

Calcium hydroxide is promising for thermal energy storage due to its low cost and high energy density. Nevertheless, the powdered material is cohesive and has low thermal conductivity which is a major challenge for the operation of moving bed reactors. One approach to facilitate the movement of the reaction bed is the stabilisation of the particles through the coating of Ca(OH)₂ granules with Al₂O₃ particles. In this work, a newly designed reactor concept was specifically developed for testing coated Ca(OH)₂ granules. The design allows for the movement of the reaction bed by gravity assistance and direct heating of the particles by a counter current gas flow. The operation was successfully demonstrated and proved to achieve high heat transfer between gas and granules. Furthermore, the movement of the reaction bed was achieved after the discharging phase. Two batches of uncoated and coated Ca(OH)₂ granules were subject of 10 thermochemical cycles in this reactor. The cycling stability, structural integrity, mechanical stability, morphology and phase composition of the granules were analysed. Full conversion of both samples was demonstrated for the entire experimental series. It was found that the alumina coating enhances the mechanical stability of the granules under reaction conditions. Full article

(This article belongs to the Special Issue Advances in Thermochemical Energy Storage)

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13 pages, 931 KiB

Open AccessEditor’s ChoiceArticle

Fast Finite-Time Stability and Its Application in Adaptive Control of High-Order Stochastic Nonlinear Systems

by Yixuan Yuan and Junsheng Zhao

Processes 2022, 10(9), 1676; https://doi.org/10.3390/pr10091676 - 23 Aug 2022

Cited by 2 | Viewed by 1459

Abstract

In this article, a new design method for an adaptive fast finite-time controller (FTC) is proposed for the finite-time stability (FTS) issue of a class of high-order stochastic nonlinear systems (HOSNSs) with unknown parameters. Using a power integrator technology and Lyapunov function approach, [...] Read more.

In this article, a new design method for an adaptive fast finite-time controller (FTC) is proposed for the finite-time stability (FTS) issue of a class of high-order stochastic nonlinear systems (HOSNSs) with unknown parameters. Using a power integrator technology and Lyapunov function approach, an adaptive state feedback controller is derived to ensure fast FTS of HOSNSs. The developed adaptive fast FTC is equipped with less settling time to obtain better steady-state accuracy compared with the traditional FTC. The effectiveness of the proposed adaptive control scheme is demonstrated by a numerical example. Full article

(This article belongs to the Special Issue Advances in Nonlinear and Stochastic System Control)

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46 pages, 7910 KiB

Open AccessEditor’s ChoiceArticle

Diffusion Coefficients in Systems Related to Reservoir Fluids: Available Data and Evaluation of Correlations

by Yibo Yang, Erling H. Stenby, Alexander A. Shapiro and Wei Yan

Processes 2022, 10(8), 1554; https://doi.org/10.3390/pr10081554 - 8 Aug 2022

Cited by 6 | Viewed by 2549

Abstract

Molecular diffusion determines the time to reach local equilibrium in a reservoir. It can be a main production mechanism in scenarios such as production from fractured reservoirs or tight formation. However, there is a lack of high-pressure diffusion coefficients for reservoir fluids and [...] Read more.

Molecular diffusion determines the time to reach local equilibrium in a reservoir. It can be a main production mechanism in scenarios such as production from fractured reservoirs or tight formation. However, there is a lack of high-pressure diffusion coefficients for reservoir fluids and its related systems. Many correlations exist, but there is no consensus on their accuracy for these systems. We provide a systematic review of the available data for systems related to reservoir fluids, as well as a comprehensive comparison of five commonly used correlations for hydrocarbon mixtures, including the extended Sigmund, Riazi-Whitson, Leahy-Dios-Firoozabadi, Wilke–Chang, and the Hayduk–Minhas correlations. We collected extensive data of diffusion coefficients in binary mixtures related to petroleum fluids and established a database of over 80 binaries and 1600 data points. We also collected the data for gas diffusion in different oils and reservoir fluids, but the data in high-pressure live oils are extremely scarce. The five correlations were evaluated using the binary database, and a few selected correlations using the oil database. None of the correlations show consistent and dominant superiority for all the binary mixtures, although some are better for particular groups/regions. For oils and reservoir fluids, the composition information is often incomplete. Only a few sets allow a comparison between different correlations. Although some trends can be identified from the correlation evaluation, no conclusive recommendation is made for a particular model, due to the data scarcity. The findings underscore the need for more accurate measurement and modeling of gas diffusion in mixtures that are more representative of reservoir fluids at high pressures. Full article

(This article belongs to the Special Issue Gas Diffusivity in Reservoir-Fluid Systems)

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13 pages, 2513 KiB

Open AccessEditor’s ChoiceArticle

Sterilizer of Knives in the Meat Industry, Working by Activating Aqueous Solutions with Glow Discharge Plasma

by Sergey V. Belov, Yury K. Danileiko, Alexey B. Egorov, Vladimir I. Lukanin, Anastasia A. Semenova, Andrey B. Lisitsyn, Natalia M. Revutskaya, Victoria V. Nasonova, Yulya K. Yushina, Etery R. Tolordava, Nazarbay A. Nasyrov, Alena I. Sinichkina, Eugeny M. Konchekov, Tatyana A. Matveeva and Sergey V. Gudkov

Processes 2022, 10(8), 1536; https://doi.org/10.3390/pr10081536 - 5 Aug 2022

Cited by 9 | Viewed by 2873

Abstract

The development of approaches for the non-thermal sterilization of instruments is an urgent task to ensure the safety of meat industry products, where the use of hot water leads to the formation of condensates and a deterioration in the hygienic condition of the [...] Read more.

The development of approaches for the non-thermal sterilization of instruments is an urgent task to ensure the safety of meat industry products, where the use of hot water leads to the formation of condensates and a deterioration in the hygienic condition of the premises. In this study, an installation for sterilizing knives was created, which works by activating aqueous salt solutions with a glow discharge. The power consumption of the installation reactor is only 125–150 Wh. The temperature rise of the sterilizing agent used is about 1.1 ± 0.2 °C/min/L. The effectiveness of the installation for plasma-activation of aqueous solutions of chloride and sodium sulfate by glow discharge (PAW) in relation to the inactivation of microorganisms, including Staphylococcus aureus, Salmonella typhimurium, Pseudomonas gessardii and L. monocytogenes, on steel surfaces was evaluated. Samples of stainless steel (parts of knives) were used in two versions (new and artificially aged). Mono- and polyspecies bacterial biofilms were grown on the surface of the samples. The treatment was carried out by immersing samples of steel plates in plasma-activated aqueous solutions. It was found that the treatment of plates in a knife sterilizer for 1 min had an effective effect on the inhibition of all types of studied bacteria. Full article

(This article belongs to the Section Food Process Engineering)

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18 pages, 6006 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Calculation of Parasitic Capacitance to Analyze Shaft Voltage of Electric Motor with Direct-Oil-Cooling System

by Chan-Ho Kim, Sung-Bae Jun, Han-Joon Yoon, Nam-Ho Kim, Ho-Chang Jung, Rae-Eun Kim and Sang-Yong Jung

Processes 2022, 10(8), 1541; https://doi.org/10.3390/pr10081541 - 5 Aug 2022

Cited by 8 | Viewed by 3707

Abstract

In modern electric vehicles, electrical failure has become a critical problem that reduces the lifetime of traction motors. Moreover, traction motors with high-voltage and high-speed systems for a high power density have been aggravating the shaft voltage problems. This study identifies that direct-oil-cooling [...] Read more.

In modern electric vehicles, electrical failure has become a critical problem that reduces the lifetime of traction motors. Moreover, traction motors with high-voltage and high-speed systems for a high power density have been aggravating the shaft voltage problems. This study identifies that direct-oil-cooling systems exacerbate this problem. To address this, an analytical method for calculating parasitic capacitance is proposed to determine the effects of cooling oil in a traction motor with a direct-oil-cooling system. Capacitance equivalent circuits are configured based on whether the slot is submerged in the cooling oil. In addition, an electric field decomposition method is applied to analyze the distortion of the electric field by the structure of the conduction parts in the motor. The results indicate that the parasitic capacitances of the traction motor are increased by the influence of the cooling oil resulting in an increase in the shaft voltage. Full article

(This article belongs to the Special Issue Design, Concepts and Applications of Electric Machines)

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24 pages, 4584 KiB

Open AccessEditor’s ChoiceArticle

A Detailed Process and Techno-Economic Analysis of Methanol Synthesis from H₂ and CO₂ with Intermediate Condensation Steps

by Bruno Lacerda de Oliveira Campos, Kelechi John, Philipp Beeskow, Karla Herrera Delgado, Stephan Pitter, Nicolaus Dahmen and Jörg Sauer

Processes 2022, 10(8), 1535; https://doi.org/10.3390/pr10081535 - 5 Aug 2022

Cited by 20 | Viewed by 11122

Abstract

In order to increase the typically low equilibrium CO₂ conversion to methanol using commercially proven technology, the addition of two intermediate condensation units between reaction steps is evaluated in this work. Detailed process simulations with heat integration and techno-economic analyses of methanol [...] Read more.

In order to increase the typically low equilibrium CO₂ conversion to methanol using commercially proven technology, the addition of two intermediate condensation units between reaction steps is evaluated in this work. Detailed process simulations with heat integration and techno-economic analyses of methanol synthesis from green H₂ and captured CO₂ are presented here, comparing the proposed process with condensation steps with the conventional approach. In the new process, a CO₂ single-pass conversion of 53.9% was achieved, which is significantly higher than the conversion of the conventional process (28.5%) and its equilibrium conversion (30.4%). Consequently, the total recycle stream flow was halved, which reduced reactant losses in the purge stream and the compression work of the recycle streams, lowering operating costs by 4.8% (61.2 M€·a⁻¹). In spite of the additional number of heat exchangers and flash drums related to the intermediate condensation units, the fixed investment costs of the improved process decreased by 22.7% (94.5 M€). This was a consequence of the increased reaction rates and lower recycle flows, reducing the required size of the main equipment. Therefore, intermediate condensation steps are beneficial for methanol synthesis from H₂/CO₂, significantly boosting CO₂ single-pass conversion, which consequently reduces both the investment and operating costs. Full article

(This article belongs to the Special Issue Industrial Chemistry Reaction: Kinetics, Mass Transfer and Industrial Reactor Design (II))

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Graphical abstract

18 pages, 10381 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Scale-Up Strategies of Jet Loop Reactors for the Intensification of Mass Transfer Limited Reactions

by Marc Maly, Steffen Schaper, Rafael Kuwertz, Marko Hoffmann, Joachim Heck and Michael Schlüter

Processes 2022, 10(8), 1531; https://doi.org/10.3390/pr10081531 - 4 Aug 2022

Cited by 4 | Viewed by 4319

Abstract

For the purpose of the intensification of an industrial-scale gas-liquid process, the implementation in an alternative reactor concept is investigated at Hamburg University of Technology (TUHH) in cooperation with Ehrfeld Mikrotechnik GmbH. Existing process operation data from a bubble column hint at a [...] Read more.

For the purpose of the intensification of an industrial-scale gas-liquid process, the implementation in an alternative reactor concept is investigated at Hamburg University of Technology (TUHH) in cooperation with Ehrfeld Mikrotechnik GmbH. Existing process operation data from a bubble column hint at a mass transfer limitation of the gas-liquid reaction. In the project, a jet loop reactor (JLR) is chosen to increase the specific interfacial area between gas and liquid, and thus increase mass transfer, while keeping the reactor system mechanically simple and low-maintenance. For the investigation, a laboratory scale reactor has been designed on the basis of an existing industrial scale process and scaled according to a pilot scale reactor available at TUHH. For scaling, geometric similarity is desired, while specific energy dissipation rate and volumetric gas input are kept constant for the chosen scale-up strategy. Between the two different scales, the reactors are successfully characterised in a water-air system with regards to the important mass transfer, among other parameters. A pressure- and chemical-resistant twin of the laboratory-scale reactor is provided to the project partner for trials under real process conditions with the original material system. The presented work shows that the JLR concept can be transferred sufficiently well between different scales when suitable parameters are chosen, and offers a wide operating window. The investigations aim to provide a basis for a future scale-up of the chemical process in the JLR system to the industrial scale. Full article

(This article belongs to the Special Issue Multiphase Mass Transfer and Phase Equilibrium in Chemical Processes)

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19 pages, 2806 KiB

Open AccessEditor’s ChoiceArticle

FTIR as a Powerful Tool for Measurements of Diffusion in Supercritical Carbon Dioxide Using Taylor Dispersion Method

by Cecilia I. A. V. Santos, Marisa C. F. Barros, Maria P. R. T. Faro, Valentina Shevtsova and Ana C. F. Ribeiro

Processes 2022, 10(8), 1528; https://doi.org/10.3390/pr10081528 - 3 Aug 2022

Cited by 3 | Viewed by 2265

Abstract

A new experimental high-pressure setup for measuring diffusion coefficients in supercritical fluids, based on Taylor dispersion method, and using an FTIR detector to operate up to 25.0 MPa was designed and optimized. Tracer diffusivities, D₁₂, of toluene and benzene in supercritical [...] Read more.

A new experimental high-pressure setup for measuring diffusion coefficients in supercritical fluids, based on Taylor dispersion method, and using an FTIR detector to operate up to 25.0 MPa was designed and optimized. Tracer diffusivities, D₁₂, of toluene and benzene in supercritical carbon dioxide were measured in the temperature range of 306.15–320.15 K, and pressure range of 7.5–17 MPa to evaluate the setup and experimental protocol. The effects of flow velocity, volume of the cell, absorbance at different wavenumbers on the diffusion coefficient as well as all parameters respecting the Taylor dispersion method have been analyzed. The obtained diffusion coefficients are in excellent agreement with the available literature data. The dependence of D₁₂ on temperature, pressure, and solvent density were examined. Some correlation models based on the hydrodynamic theory were used to estimate the diffusion coefficients in supercritical carbon dioxide, which is the best agreement obtained for an improved version of the Wilke–Chang model. Full article

(This article belongs to the Special Issue Utilization and Storage of Carbon Dioxide in Petroleum Engineering)

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11 pages, 3263 KiB

Open AccessEditor’s ChoiceArticle

Thermal Degradation Process of Ethinylestradiol—Kinetic Study

by Sebastian Simu, Adriana Ledeţi, Elena-Alina Moacă, Cornelia Păcurariu, Cristina Dehelean, Dan Navolan and Ionuţ Ledeţi

Processes 2022, 10(8), 1518; https://doi.org/10.3390/pr10081518 - 2 Aug 2022

Cited by 4 | Viewed by 2474

Abstract

The present study reports the results obtained after the analysis of the thermal stability and decomposition kinetics of widely used synthetic derivative of estradiol, ethinylestradiol (EE), as a pure active pharmaceutical ingredient. As investigational tools, Fourier transformed infrared spectroscopy (FTIR), thermal analysis, and [...] Read more.

The present study reports the results obtained after the analysis of the thermal stability and decomposition kinetics of widely used synthetic derivative of estradiol, ethinylestradiol (EE), as a pure active pharmaceutical ingredient. As investigational tools, Fourier transformed infrared spectroscopy (FTIR), thermal analysis, and decomposition kinetics modeling of EE were employed. The kinetic study was realized using three kinetic methods, namely Kissinger, Friedman, and Flynn-Wall-Ozawa. The results of the kinetic study are in good agreement, suggesting that the main decomposition process of EE that takes place in the 175–375 °C temperature range is a single-step process, invariable during the modification of heating rate of the sample. Full article

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24 pages, 3180 KiB

Open AccessEditor’s ChoiceArticle

CFD Modelling of Calcination in a Rotary Lime Kiln

by Jarod Ryan, Markus Bussmann and Nikolai DeMartini

Processes 2022, 10(8), 1516; https://doi.org/10.3390/pr10081516 - 1 Aug 2022

Cited by 10 | Viewed by 4410

Abstract

A 2D axisymmetric computational fluid dynamics (CFD) model, coupled to a 1D bed model, has been developed to capture the key processes that occur within rotary lime kilns. The model simulates the calcination reaction using a shrinking core model, and predicts the start [...] Read more.

A 2D axisymmetric computational fluid dynamics (CFD) model, coupled to a 1D bed model, has been developed to capture the key processes that occur within rotary lime kilns. The model simulates the calcination reaction using a shrinking core model, and predicts the start of calcination and the degree of calcination at the end of the kiln. The model simulates heat transfer due to radiation, convection and conduction between the gas, wall, chains, and bed. The 2D gas and 1D bed models are coupled by mass and heat sinks to simulate heat transfer, evaporation, and the calcination reaction. The model is used to simulate two industrial kilns, one wet and one dry. The steady-state simulation results are compared to mill data, and good agreement is found. A sensitivity analysis is also presented, to obtain insight on how operating conditions and model variables impact the calcination location and degree of calcination. Full article

(This article belongs to the Special Issue Chemical Process Modelling and Simulation)

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18 pages, 1080 KiB

Open AccessEditor’s ChoiceArticle

Pyrolysis of High-Density Polyethylene Waste Plastic to Liquid Fuels—Modelling and Economic Analysis

by Sharif H. Zein, Connor T. Grogan, Osman Y. Yansaneh and Aditya Putranto

Processes 2022, 10(8), 1503; https://doi.org/10.3390/pr10081503 - 29 Jul 2022

Cited by 7 | Viewed by 7146

Abstract

Recycling of waste plastics has become vital due to the threat to the environment the huge piles of those wastes represent, with research revealing High-Density Polyethylene (HDPEs) as the most dominant waste plastics. Because of their dominance and significant environmental impact, this paper [...] Read more.

Recycling of waste plastics has become vital due to the threat to the environment the huge piles of those wastes represent, with research revealing High-Density Polyethylene (HDPEs) as the most dominant waste plastics. Because of their dominance and significant environmental impact, this paper reports the economic potential of recycling HDPE waste plastic into liquid fuels via pyrolysis. A risk and benefit assessment are presented to highlight whether the process has reasonable potential prior to the analysis of its corresponding finances. Aspen HYSYS simulation models were used as the basis for the analysis. From this, preliminary cost estimations for the net present value (NPV) of the process, its economic viability, were determined. It is shown that 100 kg/h of waste is not financially sustainable. Retailing the fuel product at a competitive price of £60/barrel would ultimately bankrupt the business. This is a consequence of the extremely high production cost of £198.40/barrel inducing the complete absence of profitability. Furthermore, the operating expenditure is found to be the root cause of the consequential financial decline, totalling £1.46 million per annum. The two most detrimental expenditures for the production cost of the pyrolysis oils were the wages of the skilled operating labour and higher utility fees incurred by the extreme temperature conditions. In addition, an unrealistically optimistic sale price of £300/barrel was also applied to ascertain a positive economic incentive. Even with the increased retail price, the process’ profits are negligible and further highlight the detrimental effect of the undesirably high operational expenditures, once more signifying that the process should not commence in its current state. However, executing such a project in developing countries such as Sierra Leone, Senegal, or Kenya where utilities and manpower, among other operational components, are cheaper, is believed to complement the immense opportunity underlying pyrolysis oil production regarding production quantity and quality. Full article

(This article belongs to the Section Environmental and Green Processes)

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12 pages, 3800 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Modeling 3D Droplet Movement Using a Drop-on-Demand Inkjet Printhead Model

by Tim Tofan, Sergejus Borodinas, Rimantas Kačianauskas and Raimondas Jasevičius

Processes 2022, 10(8), 1467; https://doi.org/10.3390/pr10081467 - 27 Jul 2022

Cited by 5 | Viewed by 2254

Abstract

This article presents a numerical simulation of a printhead model for drop-on-demand (DoD) inkjet printers. A three-dimensional droplet model is provided for the numerical study of inks, ejection parameters, droplet movement, and the analysis of droplet impacts on the surface. This work is [...] Read more.

This article presents a numerical simulation of a printhead model for drop-on-demand (DoD) inkjet printers. A three-dimensional droplet model is provided for the numerical study of inks, ejection parameters, droplet movement, and the analysis of droplet impacts on the surface. This work is devoted to the analysis of different droplet ejection settings during the printing process, when the behavior of the droplet directly affects the accuracy of the printing process itself. A numerical model was also developed to investigate the effect of various settings on droplet stability, including printhead size and nozzle orifice, motion parameters (pulse strength and droplet ejection amplitude) and fluid properties. The results reflect the behavior of the ink droplet over time. The behavior of the drop was tested at different waveform ejection parameters and a mass turnover was observed. Full article

(This article belongs to the Special Issue Advanced Research and Applications of Inkjet Printing (IJP) Technique)

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19 pages, 5941 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

A Study on the Application of Discrete Wavelet Decomposition for Fault Diagnosis on a Ship Oil Purifier

by Songho Lee, Taehyun Lee, Jeongyeong Kim, Jongjik Lee, Kyungha Ryu, Yongjin Kim and Jong-Won Park

Processes 2022, 10(8), 1468; https://doi.org/10.3390/pr10081468 - 27 Jul 2022

Cited by 6 | Viewed by 1953

Abstract

With the development of the Internet of things, big data, and AI leading the 4th industrial revolution, it has become possible to acquire, manage, and analyze vast and diverse condition signals from various industrial machinery facilities. In addition, it has been revealed that [...] Read more.

With the development of the Internet of things, big data, and AI leading the 4th industrial revolution, it has become possible to acquire, manage, and analyze vast and diverse condition signals from various industrial machinery facilities. In addition, it has been revealed that various and large amounts of signals acquired from the facilities can be utilized for fault diagnosis. Currently, while data-driven fault diagnosis techniques applicable to the facilities are being developed, it has been tried to apply the techniques for the development of fully autonomous ships in the shipbuilding and shipping industry. Since the autonomous ships must be able to detect and diagnose the failures on their own in real time, the overall research is required on how to acquire signals from the ship facilities and use them to diagnose their failures. In this study, a fault diagnosis framework was proposed for condition-based maintenance (CBM) of ship oil purifiers, which are an auxiliary facility in the engine system of a ship. First, an oil purifier test-bed for simulating faults was built to obtain data on the state of the equipment. After extracting features using discrete wavelet decomposition from the data, the features were visualized by using t-distributed stochastic neighbor embedding, and were used to train support vector machine-based diagnostic models. Finally, the trained models were evaluated with

A c c u r a c y

and

F_{1} s c o r e

, and some models scored 0.99 or higher, confirming high diagnostic performance. This study can be used as a reference for establishing CBM system and fault diagnosis system. Furthermore, this study is expected to improve the safety and reliability of oil purifiers in Degree 4 MASS. Full article

(This article belongs to the Section Manufacturing Processes and Systems)

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16 pages, 19999 KiB

Open AccessEditor’s ChoiceArticle

Modal Analysis on MVG Controlled Supersonic Flow at Different Mach Numbers

by Yong Yang, Yonghua Yan, Caixia Chen, Qingquan Wu, Tor A. Kwembe and Ryan Wu

Processes 2022, 10(8), 1456; https://doi.org/10.3390/pr10081456 - 25 Jul 2022

Viewed by 1361

Abstract

Modal analysis on micro-vortex generator (MVG)-controlled supersonic flow at different Mach numbers is performed in this paper. The purpose of this investigation is to clarify the different properties of streamwise and ring-like vortical modes, and the effects of different Mach numbers on these [...] Read more.

Modal analysis on micro-vortex generator (MVG)-controlled supersonic flow at different Mach numbers is performed in this paper. The purpose of this investigation is to clarify the different properties of streamwise and ring-like vortical modes, and the effects of different Mach numbers on these modes, to further understand the vortical structures as they travel from MVG down to the shock wave/boundary-layer interaction (SWBLI) region. To this end, a high order and high resolution large eddy simulation (LES) was carried out, which identified the vortical structures behind the MVG and in the shock wave/boundary-layer interaction (SWBLI) region in the supersonic ramp flow with flow speeds of three different Mach numbers 1.5, 2.0, and 2.5. The proper orthogonal decomposition (POD) then was adopted to investigate the modes of the fluctuation flow field. It emerged that the streamwise and ring-like vortical modes were disparate in energy distribution, structural order, frequency and amplitude. Furthermore, it showed that as the Mach number increased, the energy of the streamwise modes increased while the opposite was true for ring-like modes; and the streamwise modal structures were altered more significantly than the ring-like modes, and the frequency of each mode scarcely varied. It was also found that the streamwise vortices absorbed energy from the ring-like vortices while they traveled from the MVG down to the SWBLI region, but the dominant frequency of each mode rarely changed during this process. Full article

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16 pages, 3826 KiB

Open AccessEditor’s ChoiceArticle

Inline Weld Depth Evaluation and Control Based on OCT Keyhole Depth Measurement and Fuzzy Control

by Maximilian Schmoeller, Tony Weiss, Korbinian Goetz, Christian Stadter, Christian Bernauer and Michael F. Zaeh

Processes 2022, 10(7), 1422; https://doi.org/10.3390/pr10071422 - 21 Jul 2022

Cited by 6 | Viewed by 2251

Abstract

In an industrial joining process, exemplified by deep penetration laser beam welding, ensuring a high quality of welds requires a great effort. The quality cannot be fully established by testing, but can only be produced. The fundamental requirements for a high weld seam [...] Read more.

In an industrial joining process, exemplified by deep penetration laser beam welding, ensuring a high quality of welds requires a great effort. The quality cannot be fully established by testing, but can only be produced. The fundamental requirements for a high weld seam quality in laser beam welding are therefore already laid in the process, which makes the use of control systems essential in fully automated production. With the aid of process monitoring systems that can supply data inline to a production process, the foundation is laid for the efficient and cycle-time-neutral control of welding processes. In particular, if novel, direct measurement methods, such as Optical Coherence Tomography, are used for the acquisition of direct geometric quantities, e.g., the weld penetration depth, a significant control potential can be exploited. In this work, an inline weld depth control system based on an OCT keyhole depth measurement is presented. The system is capable of automatically executing an inline control of the deep penetration welding process based only on a specified target weld depth. The performance of the control system was demonstrated on various aluminum alloys and for different penetration depths. In addition, the ability of the control to respond to unforeseen external disturbances was tested. Within the scope of this work, it was thus possible to provide an outlook on future developments in the field of laser welding technology, which could develop in the direction of an intuitive manufacturing process. This objective should be accomplished through the use of intelligent algorithms and innovative measurement technology—following the example of laser beam cutting, where the processing systems themselves have been provided with the ability to select suitable process parameters for several years now. Full article

(This article belongs to the Special Issue Manufacturing Industry 4.0: Trends and Perspectives)

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34 pages, 10872 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Modeling of Multiphase Flow, Superheat Dissipation, Particle Transport, and Capture in a Vertical and Bending Continuous Caster

by Mingyi Liang, Seong-Mook Cho, Xiaoming Ruan and Brian G. Thomas

Processes 2022, 10(7), 1429; https://doi.org/10.3390/pr10071429 - 21 Jul 2022

Cited by 5 | Viewed by 2352

Abstract

A new model of particle entrapment during continuous casting of steel is presented, which includes the effects of multiphase flow from argon gas injection and thermal buoyancy from superheat in the strand. The model simulates three different capture mechanisms, including capture by solidified [...] Read more.

A new model of particle entrapment during continuous casting of steel is presented, which includes the effects of multiphase flow from argon gas injection and thermal buoyancy from superheat in the strand. The model simulates three different capture mechanisms, including capture by solidified hooks at the meniscus, entrapment between dendrites, and engulfment by the surrounding of large particles. The fluid flow and bubble capture results are validated with plant measurements, including nail board dipping tests and ultrasonic tests, respectively, and good agreement is seen. Results suggest that the superheat has a negligible effect on the flow in the mold region. However, higher (30 K) superheat causes a more complex flow in the lower strand by creating multiple recirculation zones due to the thermal buoyancy effects. This causes less penetration deep into the strand, which leads to fewer and shallower particle captures. Lower (10 K) superheat may enable significant top surface freezing, leading to very large internal defect clusters. Lower superheat also leads to deeper meniscus hooks, which sometimes (0.003%) capture large (1 mm) bubbles. Capture bands occur near the transition line from vertical to curved, due to the downward fluid velocity balancing the particle terminal velocity, enabling capture in the relative stagnation region beneath the longitudinal recirculation zone. These findings agree with plant observations. Full article

(This article belongs to the Special Issue High-Efficiency and High-Quality Continuous Casting Processes)

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13 pages, 3885 KiB

Open AccessEditor’s ChoiceArticle

Use of 2-Ethylhexyl Nitrate for the Slow Pyrolysis of Plastic Waste

by Jochen Uebe, Audrone Zukauskaite, Zilvinas Kryzevicius and Gintare Vanagiene

Processes 2022, 10(7), 1418; https://doi.org/10.3390/pr10071418 - 20 Jul 2022

Cited by 1 | Viewed by 1805

Abstract

Plastics are widely used and are part of modern life. Recycling of plastic waste can be achieved by pyrolysis. Conventional pyrolysis of plastic waste takes place at temperatures higher than 450 °C, because the oil yield is higher. In this study, we examined [...] Read more.

Plastics are widely used and are part of modern life. Recycling of plastic waste can be achieved by pyrolysis. Conventional pyrolysis of plastic waste takes place at temperatures higher than 450 °C, because the oil yield is higher. In this study, we examined if an initiator for radical reactions can achieve the conventional pyrolysis of HDPE and PP even at low temperatures. To support the onset of decomposition of HDPE and PP at low temperatures, 2-ethylhexyl nitrate (2-EHN) was added. 2-EHN forms radicals already at about 150 °C and can thus initiate the pyrolysis process at lower temperatures. Pyrolysis oil yields increased, especially for HDPE pyrolysis, at the expense of the gaseous (minus 50%) and especially the solid fraction (minus 80%). For PP and HDPE pyrolysis oil, the proportion of carbon compounds shifted toward shorter-chain, less cyclic compounds, and there was an improvement in the physicochemical property profile: the heating values of both oils were slightly higher and the pour point significantly lower, in line with the shift toward shorter-chain compounds. The diesel content and, to a lesser extent, the gasoline content increased at the expense of waxes and other high-boiling compounds. Full article

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19 pages, 3398 KiB

Open AccessEditor’s ChoiceArticle

A Novel Exponential-Weighted Method of the Antlion Optimization Algorithm for Improving the Convergence Rate

by Szu-Chou Chen, Wen-Chen Huang, Ming-Hsien Hsueh, Chieh-Yu Pan and Chih-Hao Chang

Processes 2022, 10(7), 1413; https://doi.org/10.3390/pr10071413 - 20 Jul 2022

Cited by 4 | Viewed by 1637

Abstract

The antlion optimization algorithm (ALO) is one of the most effective algorithms to solve combinatorial optimization problems, but it has some disadvantages, such as a long runtime. As a result, this problem impedes decision makers. In addition, due to the nature of the [...] Read more.

The antlion optimization algorithm (ALO) is one of the most effective algorithms to solve combinatorial optimization problems, but it has some disadvantages, such as a long runtime. As a result, this problem impedes decision makers. In addition, due to the nature of the problem, the speed of convergence is a critical factor. As the size of the problem dimension grows, the convergence speed of the optimizer becomes increasingly significant. Many modified versions of the ALO have been developed in the past. Nevertheless, there are only a few research articles that discuss better boundary strategies that can increase the diversity of ants walking around an antlion to accelerate convergence. A novel exponential-weighted antlion optimization algorithm (EALO) is proposed in this paper to address slow convergence rates. The algorithm uses exponential functions and a random number in the interval 0, 1 to increase the diversity of the ant’s random walks. It has been demonstrated that by optimizing twelve classical objective functions of benchmark functions, the novel method has a higher convergence rate than the ALO. This is because it has the most powerful search capability and speed. In addition, the proposed method has also been compared to other existing methods, and it has obtained superior experimental results relative to compared methods. Therefore, the proposed EALO method deserves consideration as a possible optimization tool for solving combinatorial optimization problems, due to its highly competitive results. Full article

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16 pages, 26647 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Phosphorus Removal from Aerobic Granular Sludge: Proliferation of Polyphosphate-Accumulating Organisms (PAOs) under Different Feeding Strategies

by Oliver Terna Iorhemen, Sandra Ukaigwe, Hongyu Dang and Yang Liu

Processes 2022, 10(7), 1399; https://doi.org/10.3390/pr10071399 - 18 Jul 2022

Cited by 8 | Viewed by 2761

Abstract

Aerobic granular sludge (AGS) is known for high phosphorus removal from wastewaters, and phosphorus can be recovered from high phosphorus-containing waste sludge granules. This study aimed at determining the feeding strategy that provides the best performance in terms of the proliferation of polyphosphate-accumulating [...] Read more.

Aerobic granular sludge (AGS) is known for high phosphorus removal from wastewaters, and phosphorus can be recovered from high phosphorus-containing waste sludge granules. This study aimed at determining the feeding strategy that provides the best performance in terms of the proliferation of polyphosphate-accumulating organisms (PAOs) and phosphorus removal. Using three AGS bioreactors, this study compared phosphorus removal and the proliferation dynamics of PAOs under three different feeding strategies: anaerobic slow feeding (R1), pulse feeding + anaerobic mixing (R2), and pulse feeding (R3). Results indicate that R1 and R2 achieved significantly higher phosphorus removal (97.6 ± 3% for R1 and 98.3 ± 1% for R2) than R3 (55 ± 11%). The anaerobic slow feeding procedure (R1) achieved the highest specific phosphorus release rate (SPRR) and specific phosphorus uptake rate (SPUR) as compared to the other two feeding conditions. 16S ribosomal ribonucleic acid (rRNA) gene sequencing assay of the microbial community for the three feeding strategies indicated that although the feeding strategy impacted reactor performance, it did not significantly alter the microbial community. The bacteria community composition maintained a similar degree of diversity. Proteobacteria, Bacteroidetes, and Verrucomicrobia were the dominant bacterial phyla in the system. Dominant PAOs were from the class Betaproteobacteria and the genera Paracoccus and Thauera. Glycogen-accumulating organisms were significantly inhibited while other less-known bacteria such as Wandonia and Hyphomonas were observed in all three reactors. Full article

(This article belongs to the Special Issue Environmental Protection by Aerobic Granular Sludge Process)

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10 pages, 694 KiB

Open AccessEditor’s ChoiceCommunication

Measuring Total Sulphur Amount Fraction at picomol/mol in Hydrogen Fuel: New Results from cryo-GC-SCD Analytical Method

by Thomas Bacquart, Abigail Siân Olivia Morris, Sam Bartlett, Ole Kjos, Arul Murugan and Ward Storms

Processes 2022, 10(7), 1393; https://doi.org/10.3390/pr10071393 - 17 Jul 2022

Viewed by 1745

Abstract

Fuel cell electric vehicles are expanding quickly from light-duty to heavy-duty applications such as buses or trucks. Hydrogen fuel quality needs to comply with ISO14687:2019 to avoid any improper performance of the vehicles. Total sulphur is one of the most impactful contaminants to [...] Read more.

Fuel cell electric vehicles are expanding quickly from light-duty to heavy-duty applications such as buses or trucks. Hydrogen fuel quality needs to comply with ISO14687:2019 to avoid any improper performance of the vehicles. Total sulphur is one of the most impactful contaminants to a fuel cell system and has a threshold of 4 nmol/mol. Most analytical methods provide a limit of detection (LOD) of 1 nmol/mol for total sulphur in hydrogen. Total sulphur is often not quantified and reported as below LOD due to lack of sensitivity. A new analytical method using cryo-focussing gas chromatography with sulphur chemiluminescence detector (cryo-GC-SCD) was developed for picomol/mol analysis of total sulphur. The method achieved linearity between 150–16,000 picomol/mol, validated against NPL reference materials, and relative expanded uncertainty of 21% (k = 2). Samples from 11 hydrogen refuelling stations (HRS) were analysed using this method. The total sulphur amount fraction for all the HRSs was more than 10 times lower than the actual ISO14687:2019 threshold with highest value around 290 picomol/mol. The study demonstrated that the cryo-GC-SCD method can measure total sulphur at picomol/mol in hydrogen fuel. Additionally, it provided the first results on sulphur compound stability in an aluminium gas cylinder for which further study is needed. Full article

(This article belongs to the Section Energy Systems)

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16 pages, 1780 KiB

Open AccessEditor’s ChoiceArticle

Effect of the Gas Diffusion Layer Design on the Water Management and Cell Performance of a PEM Fuel Cell

by Antonio Martín-Alcántara, Laura González-Morán, Javier Pino, José Guerra and Alfredo Iranzo

Processes 2022, 10(7), 1395; https://doi.org/10.3390/pr10071395 - 17 Jul 2022

Cited by 11 | Viewed by 2277

Abstract

The influence of the different properties of the gas diffusion layer (GDL) on the operation of a liquid-cooled, proton-exchange polymer electrolyte fuel cell (PEMFC) has been studied in this work. Three-dimensional numerical simulations (CFD) have been conducted to compare several commercial GDLs with [...] Read more.

The influence of the different properties of the gas diffusion layer (GDL) on the operation of a liquid-cooled, proton-exchange polymer electrolyte fuel cell (PEMFC) has been studied in this work. Three-dimensional numerical simulations (CFD) have been conducted to compare several commercial GDLs with different properties, analyzing their influence on the cell performance. Specifically, four GDLs (AvCarb P-75, SIGRACET 34BC, SIGRACET 34BA and Toray TGP-H-090) have been studied, two of them including a microporous layer (MPL). The effect of the MPL has been inspected by contrast of the results obtained with the same GDL, with or without MPL. Potentiostatic boundary conditions have been applied, varying the electric potential between 1.05 and 0.35 V to obtain a representative

i - V

curve with enough resolution. Detailed postprocessing tasks were carried out to gain a deeper understanding on the phenomena occurring within the cell for each GDL. It can be concluded from this work that a high electrical conductivity and a high permeability lead to a better fuel cell performance. On the other hand, although the presence of MPL provides lower permeability leading to a worse overall performance, it has been shown that the lack of it may result in membrane dehydration and cell degradation issues. Full article

(This article belongs to the Special Issue Experimental Analysis and Numerical Simulation of Fuel Cells)

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19 pages, 2534 KiB

Open AccessEditor’s ChoiceArticle

Comparison of Different Approaches to the Creation of a Mathematical Model of Melt Temperature in an LD Converter

by Marek Laciak, Ján Kačur, Ján Terpák, Milan Durdán and Patrik Flegner

Processes 2022, 10(7), 1378; https://doi.org/10.3390/pr10071378 - 14 Jul 2022

Cited by 3 | Viewed by 1674

Abstract

In the steel production process in the LD converter, it is important to have information about the melt temperature. The temperature and chemical composition of the steel are important parameters in this process in terms of its completion. During the process, continuous measurement [...] Read more.

In the steel production process in the LD converter, it is important to have information about the melt temperature. The temperature and chemical composition of the steel are important parameters in this process in terms of its completion. During the process, continuous measurement of the melt temperature and thus also information about the end of the process are missing. This paper describes three approaches to creating a mathematical model of melt temperature. The first approach is a regression model, which predicts an immeasurable melt temperature based on other directly measured process variables. The second approach to creating a mathematical model is based on the machine learning method. Simple and efficient learning algorithms characterize the machine learning methods. We used support vector regression (SVR) method and the adaptive neuro-fuzzy inference system (ANFIS) to create a mathematical model of the melt temperature. The third approach is the deterministic approach, which is based on the decomposition of the process and its heat balance. The mathematical models that were compiled based on the mentioned approaches were verified and compared to real process data. Full article

(This article belongs to the Special Issue Synergies in Combined Development of Processes and Models)

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22 pages, 2788 KiB

Open AccessEditor’s ChoiceArticle

Ergonomic Risk Minimization in the Portuguese Wine Industry: A Task Scheduling Optimization Method Based on the Ant Colony Optimization Algorithm

by António Agrela Freitas, Tânia Miranda Lima and Pedro Dinis Gaspar

Processes 2022, 10(7), 1364; https://doi.org/10.3390/pr10071364 - 13 Jul 2022

Cited by 5 | Viewed by 1857

Abstract

In the wine industry, task planning is based on decision-making processes that are influenced by technical and organizational constraints as well as regulatory limitations. A characteristic constraint inherent to this sector concerns occupational risks, in which companies must reduce and mitigate work-related accidents, [...] Read more.

In the wine industry, task planning is based on decision-making processes that are influenced by technical and organizational constraints as well as regulatory limitations. A characteristic constraint inherent to this sector concerns occupational risks, in which companies must reduce and mitigate work-related accidents, resulting in lower operating costs and a gain in human, financial, and material efficiency. This work proposes a task scheduling optimization model using a methodology based on the ant colony optimization approach to mitigate the ergonomic risks identified in general winery production processes by estimating the metabolic energy expenditure during the execution of tasks. The results show that the tasks were reorganized according to their degree of ergonomic risk, preserving an acceptable priority sequence of tasks with operational affinity and satisfactory efficiency from the point of view of the operationalization of processes, while the potential ergonomic risks are simultaneously minimized by the rotation and alternation of operative teams between those tasks with higher and lower values of metabolic energy required. We also verified that tasks with lower ergonomic-load requirements influence the reorganization of the task sequence by lowering the overall value of metabolic energy, which is reflected in the reduction of the ergonomic load. Full article

(This article belongs to the Special Issue Optimization Algorithms Applied to Sustainable Production Processes)

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21 pages, 3474 KiB

Open AccessEditor’s ChoiceArticle

Investigating Aluminum Tri-Hydroxide Production from Sodium Aluminate Solutions in the Pedersen Process

by James Malumbo Mwase, Michail Vafeias, Danai Marinos, Panias Dimitrios and Jafar Safarian

Processes 2022, 10(7), 1370; https://doi.org/10.3390/pr10071370 - 13 Jul 2022

Cited by 6 | Viewed by 3088

Abstract

This study investigates applying the principles of the long-discontinued Pedersen process as a possible route for producing metallurgical grade alumina from low-grade and secondary feed materials. The investigation focused on the hydrometallurgical steps in the process, namely leaching, desilication, and precipitation, and adapting [...] Read more.

This study investigates applying the principles of the long-discontinued Pedersen process as a possible route for producing metallurgical grade alumina from low-grade and secondary feed materials. The investigation focused on the hydrometallurgical steps in the process, namely leaching, desilication, and precipitation, and adapting it to valorize bauxite residue. The test material used was a calcium–aluminate slag made by the smelting-reduction of a mixture of bauxite residue (dewatered red mud) and a calcium-rich bauxite beneficiation by-product. Samples of the slag were leached in a 1 L jacketed glass reactor with Na₂CO₃ solution, varying Na₂CO₃ concentration and leaching time. Additionally, different approaches to leaching involving mechanical treatment of the leached slag and re-leaching using either fresh or recycled solution were also explored. The desilication step was carried out by treating the leachate solution with powdered CaO, varying the amounts of CaO used. Finally, the desilicated leach solution was sparged with a CO₂ gas mixture, after which the precipitate was allowed to age in the solution. The carbonation and aging temperatures and times were varied. As much as 67% of the Al was leached from the slag. The desilication process successfully removed 88% of the Si. The precipitation process produced a product composed mostly of bayerite [Al(OH)₃], but some tests had considerable amounts of the unwanted phase dawsonite [NaAlCO₃(OH)₂]. The results indicated that the highest Al recovery was obtained using low concentrations of Na₂CO₃ solutions, and aluminum tri hydroxide is formed from these solutions at low temperatures at a fast rate compared to higher solution concentrations and temperatures. Full article

(This article belongs to the Section Chemical Processes and Systems)

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12 pages, 4366 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Study of the Polishing Characteristics by Abrasive Flow Machining with a Rotating Device

by Ken-Chuan Cheng, A-Cheng Wang, Kuan-Yu Chen and Chien-Yao Huang

Processes 2022, 10(7), 1362; https://doi.org/10.3390/pr10071362 - 13 Jul 2022

Cited by 7 | Viewed by 2277

Abstract

Since only uni-direction motion is produced by traditional abrasive flow machining (AFM), so the polishing effects of the inner hole is not easy to achieve uniform roughness of the whole surface after polishing. Therefore, in this study, a rotating device with a DC [...] Read more.

Since only uni-direction motion is produced by traditional abrasive flow machining (AFM), so the polishing effects of the inner hole is not easy to achieve uniform roughness of the whole surface after polishing. Therefore, in this study, a rotating device with a DC servo motor was set up in the AFM to increase the tangential forces on the machining surface, and therefore, improve the uniform surface roughness and polishing efficiency. The rotating device was designed by a group of transmission gear set and a DC servo motor to create a rotational finishing path for the abrasive medium. The rotational motion of an abrasive can create different tangential forces on the working surface, inducing a more complex polishing path than that of traditional AFM. In addition to rotational speed, a servo motor can also change rotation directions in one working process, causing an abrasive medium to create many irregular finishing paths in the AFM. The experimental results showed that the surface roughness of the workpiece was significantly decreased with an increase in the rotational speed. Additionally, the results also showed that the surface roughness (SR) of the inner hole decreased from 0.61 μm Ra to 0.082 μm Ra after 20 machining cycles, the surface roughness improvement rate reached 87% at 15 rpm rotational speed, by applying a 1.5:1 silicone gel/abrasive concentration ratio and #60 abrasive mesh in the experiments. This study created excellent polishing efficiency by using a servo rotational device with AFM to produce good surface quality. Full article

(This article belongs to the Special Issue New Frontiers in Magnetic Polishing and Electrochemical Technology)

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16 pages, 27560 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

A Study on Deep Learning-Based Fault Diagnosis and Classification for Marine Engine System Auxiliary Equipment

by Jeong-yeong Kim, Tae-hyun Lee, Song-ho Lee, Jong-jik Lee, Won-kyun Lee, Yong-jin Kim and Jong-won Park

Processes 2022, 10(7), 1345; https://doi.org/10.3390/pr10071345 - 11 Jul 2022

Cited by 9 | Viewed by 2457

Abstract

Maritime autonomous surface ships (MASS) are proposed as a future technology of the maritime industry. One of the key technologies for the development of MASS is condition-based maintenance (CBM) based on prognostics and health management (PHM). The CBM technology can be used for [...] Read more.

Maritime autonomous surface ships (MASS) are proposed as a future technology of the maritime industry. One of the key technologies for the development of MASS is condition-based maintenance (CBM) based on prognostics and health management (PHM). The CBM technology can be used for early detection of abnormalities based on the database and for a prediction of the fault occurring in the future. However, this technology has a problem that requires a high-quality database that reproduces the operation state of the actual ships and quantitatively and systematically indicates the characteristics for the various fault state of the device. To solve this problem, this paper presents a study on the development method of the fault database based on the reliability. Firstly, the reliability analysis of the target device was performed to select five types of the core fault modes. After that, a fault simulation scenario that defined the fault simulation test methodology was drawn. A land-based testbed was built for the fault simulation test. The fault simulation database was developed with a total of 109 sets through the fault simulation test. Additionally, a fault classification algorithm based on deep learning is proposed. The classification performance was evaluated with a confusion matrix. The developed database will be expected to serve as the basis for the development CBM technology of MASS in the future. Full article

(This article belongs to the Section Manufacturing Processes and Systems)

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19 pages, 1853 KiB

Open AccessEditor’s ChoiceArticle

Overview of Different Modes and Applications of Liquid Phase-Based Microextraction Techniques

by José S. Câmara, Rosa Perestrelo, Basit Olayanju, Cristina V. Berenguer, Abuzar Kabir and Jorge A. M. Pereira

Processes 2022, 10(7), 1347; https://doi.org/10.3390/pr10071347 - 11 Jul 2022

Cited by 9 | Viewed by 3791

Abstract

Liquid phase-based microextraction techniques (LPµETs) have attracted great attention from the scientific community since their invention and implementation mainly due to their high efficiency, low solvent and sample amount, enhanced selectivity and precision, and good reproducibility for a wide range of analytes. This [...] Read more.

Liquid phase-based microextraction techniques (LPµETs) have attracted great attention from the scientific community since their invention and implementation mainly due to their high efficiency, low solvent and sample amount, enhanced selectivity and precision, and good reproducibility for a wide range of analytes. This review explores the different possibilities and applications of LPμETs including dispersive liquid–liquid microextraction (DLLME) and single-drop microextraction (SDME), highlighting its two main approaches, direct immersion-SDME and headspace-SDME, hollow-fiber liquid-phase microextraction (HF-LPME) in its two- and three-phase device modes using the donor–acceptor interactions, and electro membrane extraction (EME). Currently, these LPμETs are used in very different areas of interest, from the environment to food and beverages, pharmaceutical, clinical, and forensic analysis. Several important potential applications of each technique will be reported, highlighting its advantages and drawbacks. Moreover, the use of alternative and efficient “green” extraction solvents including nanostructured supramolecular solvents (SUPRASs, deep eutectic solvents (DES), and ionic liquids (ILs)) will be discussed. Full article

(This article belongs to the Special Issue Control and Optimization of Extractive Methodologies and Analysis of Natural Products)

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15 pages, 1185 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Valorization of Spent Sugarcane Fermentation Broth as a Source of Phenolic Compounds

by Carla Maria Oliveira, Bruno Horta, Tânia Leal, Manuela Pintado and Catarina S. S. Oliveira

Processes 2022, 10(7), 1339; https://doi.org/10.3390/pr10071339 - 8 Jul 2022

Cited by 3 | Viewed by 2130

Abstract

A methodology based on a solid phase extraction (SPE) was optimized for the recovery of phenolic compounds from the spent fermentation broth generated from Biofene^® (trans-β-farnesene) production. For this purpose, two resins (XAD-2 and HP-20) and three desorption solutions (water, [...] Read more.

A methodology based on a solid phase extraction (SPE) was optimized for the recovery of phenolic compounds from the spent fermentation broth generated from Biofene^® (trans-β-farnesene) production. For this purpose, two resins (XAD-2 and HP-20) and three desorption solutions (water, 50/50 ethanol/water, and ethanol) were tested. The most efficient resin revealed to be the HP-20, using ethanol as desorption solution, reaching an overall total phenolic compound recovery of ca. 80% when 6 BV (bed volume) of both feed and ethanol were applied. The optimization of the resin’s process cycle pointed to 15 BV feed to be treated per cycle and using the same volume of ethanol in the desorption step, with no need for an extra resin regeneration step, stably yielding 48% total phenolic compound recovery from the spent broth for at least 4 cycles, translating into 60 BV of feed being treated per BV of resin, and with the resin being still perfectly active. The extract was characterized using LC−ESI−UHR−QqTOF−MS, and a total of 82 and 15 compounds were identified, in negative and positive ionization modes, respectively. Organic acids were the main class of compounds identified in the phenolic-rich extract, followed by phenolic compounds, saccharides, peptides or amino acids and vitamins. Additionally, the extract revealed a significant antioxidant capacity (914.1 ± 51.6 and 2764.5 ± 142.8 µmol Trolox equivalents/g-dw, respectively, with ABTS and ORAC methodologies), which might be interesting for a wide variety of applications. Full article

(This article belongs to the Special Issue Value-Added Utilization Processes of Industrial Wastes)

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14 pages, 4636 KiB

Open AccessEditor’s ChoiceArticle

Oxidation during Fresh Plant Processing: A Race against Time

by Didier Barmaverain, Samuel Hasler, Christoph Kalbermatten, Matthias Plath and Roger Kalbermatten

Processes 2022, 10(7), 1335; https://doi.org/10.3390/pr10071335 - 8 Jul 2022

Cited by 5 | Viewed by 3129

Abstract

Oxidation is a major concern in the food and cosmetics industry; however, little information is available in the literature about its effect during the production of herbal medicines. The impact of oxidation on herbal mother tincture (MT) manufacturing was investigated by performing an [...] Read more.

Oxidation is a major concern in the food and cosmetics industry; however, little information is available in the literature about its effect during the production of herbal medicines. The impact of oxidation on herbal mother tincture (MT) manufacturing was investigated by performing an oxidative stress test, in which cryogenically ground fresh plants (Echinacea purpurea, Mentha piperita, Ginkgo biloba, and Hypericum perforatum) were exposed to air in a time-controlled manner before extraction. The effect of oxidation on the resulting extracts was evaluated using UV–Vis spectroscopy and potassium permanganate antioxidant assay. Furthermore, a tyrosinase enzymatic assay was performed on MTs to evaluate the behavior of the absorbance spectra of phenolic compounds during oxidation. Additionally, several commercially available herbal mother tinctures were examined for oxidative changes. The exposure of the fresh plant material to air for 30 min decreased the antioxidant activity in all four tested plants by 10% to 44%. This decrease occurred along with an intensity diminution and flattening of the typical UV–Vis absorption spectra of the MTs. The results have shown that the impact of oxidation during MT manufacturing is a serious issue and could be monitored by means of simple UV–Vis spectra recording. Full article

(This article belongs to the Special Issue Bioactive Compounds from Natural Plants)

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10 pages, 781 KiB

Open AccessEditor’s ChoiceArticle

Simple Particle Relaxation Modeling in One-Dimensional Oscillating Flows

by Stefan Heidinger, Simon Unz and Michael Beckmann

Processes 2022, 10(7), 1322; https://doi.org/10.3390/pr10071322 - 5 Jul 2022

Cited by 3 | Viewed by 1460

Abstract

The relaxation of a rigid particle suspended in a one-dimensional oscillating flow is calculated according to different drag models and the results are compared. Conditions are derived under which relaxation can be neglected or drag models can be substituted by simpler ones. This [...] Read more.

The relaxation of a rigid particle suspended in a one-dimensional oscillating flow is calculated according to different drag models and the results are compared. Conditions are derived under which relaxation can be neglected or drag models can be substituted by simpler ones. This investigation is conducted analytically and graphically via the plane defined by the Reynolds number and amplitude parameter. This work matches various, mostly analytic drag models together to consider simple particle relaxation with a few, broad range input parameters and cover large parts of the plane spanned by Reynolds number and amplitude parameter. Full article

(This article belongs to the Special Issue Multiphase Flows and Particle Technology)

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13 pages, 4514 KiB

Open AccessEditor’s ChoiceArticle

An Investigation on the Features of Deformation and Residual Stress Generated by Patch Welding with Different Plate Sizes

by Takehito Hashiguchi, Mikihito Hirohata and Károly Jármai

Processes 2022, 10(7), 1312; https://doi.org/10.3390/pr10071312 - 4 Jul 2022

Cited by 2 | Viewed by 1718

Abstract

Welding is widely used to manufacture and repair steel structures such as piping and pressure vessels. Welding induces deformation and residual stress, which influences the mechanical performance of the structural members. Noting patch welding, which is applied to repair steel structures, a series [...] Read more.

Welding is widely used to manufacture and repair steel structures such as piping and pressure vessels. Welding induces deformation and residual stress, which influences the mechanical performance of the structural members. Noting patch welding, which is applied to repair steel structures, a series of patch welding experiments and numerical analyses were carried out. The features of out-of-plane deformation and residual stress by patch welding were examined by changing the patch size. The out-of-plane deformation showed different modes in the patch joints. The magnitude of the out-of-plane deformation depended on the patch size. The tensile residual stress at the weld toe increased with the enlargement of the patch size. The costs for the different sizes of patch welding were estimated for choosing the patch size reasonably. The patch size should be determined by considering the mechanical influences of welding and the economic viewpoints of the welding process. Full article

(This article belongs to the Special Issue Chemical Engineering and Technology)

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18 pages, 1420 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Effects of Water Content and Irrigation of Packing Materials on the Performance of Biofilters and Biotrickling Filters: A Review

by Vaidotas Danila, Alvydas Zagorskis and Tomas Januševičius

Processes 2022, 10(7), 1304; https://doi.org/10.3390/pr10071304 - 1 Jul 2022

Cited by 9 | Viewed by 2548

Abstract

Biofilters (BFs) and biotrickling filters (BTFs) are two types of bioreactors used for treatment of volatile organic compounds (VOCs). Both BFs and BTFs use packing materials in which various microorganisms are immobilised. The water phase in BFs is stationary and used to maintain [...] Read more.

Biofilters (BFs) and biotrickling filters (BTFs) are two types of bioreactors used for treatment of volatile organic compounds (VOCs). Both BFs and BTFs use packing materials in which various microorganisms are immobilised. The water phase in BFs is stationary and used to maintain the humidity of packing materials, while BTFs have a mobile liquid phase. Optimisation of irrigation of packing materials is crucial for effective performance of BFs and BTFs. A literature review is presented on the influence of water content of packing materials on the biofiltration efficiency of various pollutants. Different configurations of BFs and BTFs and their influence on moisture distribution in packing materials were discussed. The review also presents various packing materials and their irrigation control strategies applied in recent biofiltration studies. The sources of this review included recent research articles from scientific journals and several review articles discussing BFs and BTFs. Full article

(This article belongs to the Special Issue Recent Advances in Biofilter Process Treatment)

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15 pages, 3628 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

A Modification of the ABTS^• Decolorization Method and an Insight into Its Mechanism

by Kacper Kut, Bogumił Cieniek, Ireneusz Stefaniuk, Grzegorz Bartosz and Izabela Sadowska-Bartosz

Processes 2022, 10(7), 1288; https://doi.org/10.3390/pr10071288 - 30 Jun 2022

Cited by 18 | Viewed by 3057

Abstract

A modification of the ABTS^• decolorization assay for plate readers is presented. In our modification, 200 µL of ABTS solution of absorbance 1.0 at 734 nm was added with an antioxidant and decreased absorbance resulted. For comparison of antioxidant activities in the [...] Read more.

A modification of the ABTS^• decolorization assay for plate readers is presented. In our modification, 200 µL of ABTS solution of absorbance 1.0 at 734 nm was added with an antioxidant and decreased absorbance resulted. For comparison of antioxidant activities in the kinetic assay of absorbance decrease, concentration dependence of absorbance decrease and of area under curve are recommended. “Fast” and “slow” antioxidants were distinguished: while the reactions of “fast” antioxidants ABTS^• were completed within seconds, the reactions of “slow” antioxidants were not finished after 6 min. We recommend reaction time of 60 min for assays of such antioxidants, blood plasma and plant extracts. Sub-additive interactions between some antioxidants (ascorbate and Trolox, hispidulin and Trolox, and glutathione and ascorbate) were found in the ABTS^• decolorization; possible reasons for such interactions are discussed. Full article

(This article belongs to the Section Biological Processes and Systems)

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21 pages, 3470 KiB

Open AccessEditor’s ChoiceArticle

Model-Based Investigation of the Interaction of Gas-Consuming Reactions and Internal Circulation Flow within Jet Loop Reactors

by Ferdinand Breit, Oliver Bey and Erik von Harbou

Processes 2022, 10(7), 1297; https://doi.org/10.3390/pr10071297 - 30 Jun 2022

Cited by 2 | Viewed by 2372

Abstract

Jet loop reactors are standard multiphase reactors used in chemical, biological and environmental processes. The strong liquid jet provided by a nozzle enforces both internal circulation of liquid and gas as well as entrainment and dispersion of the gas phase. We present a [...] Read more.

Jet loop reactors are standard multiphase reactors used in chemical, biological and environmental processes. The strong liquid jet provided by a nozzle enforces both internal circulation of liquid and gas as well as entrainment and dispersion of the gas phase. We present a one-dimensional compartment model based on a momentum balance that describes the internal circulation of gas and liquid phase in the jet loop reactor. This model considers the influence of local variations of the gas volume fraction on the internal circulation. These local variations can be caused by coalescence of gas bubbles, additional gas-feeding points and gas consumption or production. In this work, we applied the model to study the influence of a gas-consuming reaction on the internal circulation. In a comprehensive sensitivity analysis, the interaction of different parameters such as rate of reaction, power input through the nozzle, gas holdup, reactor geometry, and circulation rate were investigated. The results show that gas consumption can have a significant impact on internal circulation. Industrially relevant operating conditions have even been found where the internal circulation comes to a complete standstill. Full article

(This article belongs to the Special Issue Multiphase Reaction Process Design and Optimization)

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28 pages, 1623 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Characterization of Slaughterhouse Wastewater and Development of Treatment Techniques: A Review

by Mary Ng, Sadou Dalhatou, Jessica Wilson, Boniface Pone Kamdem, Mercy Bankole Temitope, Hugues Kamdem Paumo, Hayet Djelal, Aymen Amine Assadi, Phuong Nguyen-Tri and Abdoulaye Kane

Processes 2022, 10(7), 1300; https://doi.org/10.3390/pr10071300 - 30 Jun 2022

Cited by 29 | Viewed by 10882

Abstract

Commercialization in the meat-processing industry has emerged as one of the major agrobusiness challenges due to the large volume of wastewater produced during slaughtering and cleaning of slaughtering facilities. Slaughterhouse wastewater (SWW) contains proteins, fats, high organic contents, microbes, and other emerging pollutants [...] Read more.

Commercialization in the meat-processing industry has emerged as one of the major agrobusiness challenges due to the large volume of wastewater produced during slaughtering and cleaning of slaughtering facilities. Slaughterhouse wastewater (SWW) contains proteins, fats, high organic contents, microbes, and other emerging pollutants (pharmaceutical and veterinary residues). It is important to first characterize the wastewater so that adequate treatment techniques can be employed so that discharge of this wastewater does not negatively impact the environment. Conventional characterization bulk parameters of slaughterhouse wastewater include pH, color, turbidity, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC), total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP), and coliform counts. Characterization studies conducted have revealed the effects of the pollutants on microbial activity of SWW through identification of toxicity of antibiotic-resistant strains of bacteria. Due to the high-strength characteristics and complex recalcitrant pollutants, treatment techniques through combined processes such as anaerobic digestion coupled with advanced oxidation process were found to be more effective than stand-alone methods. Hence, there is need to explore and evaluate innovative treatments and techniques to provide a comprehensive summary of processes that can reduce the toxicity of slaughterhouse wastewater to the environment. This work presents a review of recent studies on the characterization of SWW, innovative treatments and technologies, and critical assessment for future research. Full article

(This article belongs to the Special Issue Application of Environmentally Friendly Technologies in Green Processes)

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17 pages, 4737 KiB

Open AccessEditor’s ChoiceArticle

Strengthening Criteria Independence through Optimization of Alternative Value Ratio Comparisons

by Joseph Kristbaum and Frank Ciarallo

Processes 2022, 10(7), 1301; https://doi.org/10.3390/pr10071301 - 30 Jun 2022

Viewed by 1238

Abstract

Every decision maker’s internal scale is different based on a myriad of possible factors unique to that decision maker. Conflicting criteria within and between alternatives in multicriteria decision making can create negative effects within the weighting schemes and amplify preference biases and scale [...] Read more.

Every decision maker’s internal scale is different based on a myriad of possible factors unique to that decision maker. Conflicting criteria within and between alternatives in multicriteria decision making can create negative effects within the weighting schemes and amplify preference biases and scale disparities between decision makers in a group decision context. Additionally, the weighting of group decision-making frameworks can intensify the already skewed criteria values. When making judgments against requirements, it may be preferable to reduce scale trend distortions between decision makers as much as possible. Previous research supports that certain information presentation modes can significantly reduce preference bias and strengthen criteria independence against requirements through cross alternative anchoring. This paper expands that research and proposes a new optimization model for strengthening criteria independence and consensus in group decision making. Initial results indicate the proposed optimization model can significantly reduce scale distortions and smooth comparative alternative value trends between decision makers toward strengthened group consensus. Furthermore, results support the potential and opportunity for semiautonomous group consensus processes. Full article

(This article belongs to the Special Issue Advanced Multiple Criteria Decision-Making Methods for Novel Applications)

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29 pages, 7925 KiB

Open AccessEditor’s ChoiceArticle

Product-Property Guided Scale-Up of a Fluidized Bed Spray Granulation Process Using the CFD-DEM Method

by Paul Kieckhefen, Swantje Pietsch-Braune and Stefan Heinrich

Processes 2022, 10(7), 1291; https://doi.org/10.3390/pr10071291 - 30 Jun 2022

Cited by 6 | Viewed by 2364

Abstract

In this work, a method to predict the surface structures of particles produced by fluidized bed spray layering granulation using the CFD-DEM method was developed. A simple state-variable/event tracking approach was implemented to capture indirect quantifiers of the progression of structure-forming microprocesses. The [...] Read more.

In this work, a method to predict the surface structures of particles produced by fluidized bed spray layering granulation using the CFD-DEM method was developed. A simple state-variable/event tracking approach was implemented to capture indirect quantifiers of the progression of structure-forming microprocesses. The state of the droplet at the time of impact on the particle surface, as well as the time required for drying, is correlated to product properties that quantify surface structure morphology such as roughness. A workflow for scale-up of fluidized bed granulation guided by product-property predictors is presented. The approach was tested on a demonstration case from the literature, where a particle core is coated with sodium benzoate solution. The experiment was scaled-up by a factor of eight to pilot-scale using the developed method. Varying the number of nozzles in use in the pilot-scale granulation affected the particle surface roughness due to the differing drying conditions encountered. On this basis, the ability of the tracked-quantity approach to capture the relationship between product properties and geometric feature or process conditions is demonstrated. Full article

(This article belongs to the Special Issue Computational and Experimental Study of Granulation in Fluidized Beds)

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15 pages, 605 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

A Fuzzy System Based Iterative Learning Control for Nonlinear Discrete-Time Systems with Iteration-Varying Uncertainties

by Chiang-Ju Chien and Ying-Chung Wang

Processes 2022, 10(7), 1275; https://doi.org/10.3390/pr10071275 - 29 Jun 2022

Cited by 2 | Viewed by 1341

Abstract

In this paper, we consider an iterative learning control problem for a class of unknown discrete-time nonlinear systems with iteration-varying initial error, iteration-varying system parameters, iteration-varying external disturbance, iteration-varying desired output, and iteration-varying control direction. These iteration-varying uncertainties are not required to take [...] Read more.

In this paper, we consider an iterative learning control problem for a class of unknown discrete-time nonlinear systems with iteration-varying initial error, iteration-varying system parameters, iteration-varying external disturbance, iteration-varying desired output, and iteration-varying control direction. These iteration-varying uncertainties are not required to take any particular structure such as the high-order internal model and only need to satisfy certain boundedness conditions. We propose an iterative learning control law with an adaptive iteration-varying fuzzy system to overcome all the uncertainties and achieve the learning control objective. Furthermore, we present a sufficient condition for designing adaptive gains and prove the convergence of the learning error to a small value as the trial number is large enough. Finally, we use two simulation examples to demonstrate all the theoretical results. Full article

(This article belongs to the Special Issue Application of Fuzzy Control in Computational Intelligence)

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17 pages, 1573 KiB

Open AccessEditor’s ChoiceArticle

Quantitative Structure-Property Relationship (QSPR) of Plant Phenolic Compounds in Rapeseed Oil and Comparison of Antioxidant Measurement Methods

by Melanie Platzer, Sandra Kiese, Tobias Asam, Franziska Schneider, Thorsten Tybussek, Thomas Herfellner, Ute Schweiggert-Weisz and Peter Eisner

Processes 2022, 10(7), 1281; https://doi.org/10.3390/pr10071281 - 29 Jun 2022

Viewed by 1719

Abstract

Natural antioxidants are known for their ability to scavenge free radicals and protect oils from oxidation. Our aim was to study the structural properties such as the number of hydroxyl groups and Bors criteria of phenolic substances leading to high antioxidant activity in [...] Read more.

Natural antioxidants are known for their ability to scavenge free radicals and protect oils from oxidation. Our aim was to study the structural properties such as the number of hydroxyl groups and Bors criteria of phenolic substances leading to high antioxidant activity in oil in order to analyze common trends and differences in widespread in vitro antioxidant assays. Therefore, 20 different phenolic substances were incorporated into rapeseed oil and were measured using pressurized differential scanning calorimetry (P-DSC) and the Rancimat method. The Bors criteria had the highest influence on the antioxidant effect in rapeseed oil, which is why myricetin (MYR), fulfilling all Bors criteria, reached the highest result of the flavonoids. In the Rancimat test and P-DSC, MYR obtained an increase in oxidation induction time (OIT) of 231.1 ± 44.6% and 96.8 ± 1.8%, respectively. Due to differences in the measurement parameters, the results of the Rancimat test and P-DSC were only partially in agreement. Furthermore, we compared the results to in vitro assays (ABTS, DPPH, FC and ORAC) in order to evaluate their applicability as alternative rapid methods. These analysis showed the highest correlation of the oil methods with the results of the DPPH assay, which is, therefore, most suitable to predict the antioxidant behavior of oil. Full article

(This article belongs to the Special Issue Total Antioxidant Capacity: Idea, Methods and Limitations)

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13 pages, 3679 KiB

Open AccessEditor’s ChoiceArticle

High Surface Area–Activated Carbon Production from Cow Manure Controlled by Heat Treatment Conditions

by Jung Eun Park, Gi Bbum Lee, Ho Kim and Bum Ui Hong

Processes 2022, 10(7), 1282; https://doi.org/10.3390/pr10071282 - 29 Jun 2022

Cited by 2 | Viewed by 4589

Abstract

In this study, methods of adding value to cow manure were studied. Due to the properties of cow manure, activated carbon with a high surface area can only be produced by increasing the fixed carbon ratio and removing the ash content. Activated carbon [...] Read more.

In this study, methods of adding value to cow manure were studied. Due to the properties of cow manure, activated carbon with a high surface area can only be produced by increasing the fixed carbon ratio and removing the ash content. Activated carbon was fabricated using five different treatments: (1) raw material–chemical activation, (2) raw material–hydrothermal carbonization–chemical activation, (3) raw material–hydrothermal carbonization–chemical activation–acid washing, (4) raw material–hydrothermal carbonization–heat treatment–chemical activation, and (5) raw material–hydrothermal carbonization–chemical activation–acid washing. The products then underwent proximate, elementary, and surface area analyses. In addition, changes in activated carbon properties depending on the heat treatment temperature (300, 500, 700 °C) and the applied chemical activator ratios (1:1–1:3) were examined. The results showed that the best heat treatment temperature was 300 °C, and the cow manure to chemical activator ratio was 1:2. The heat treatment stabilization process increases the fixed carbon ratio and the solid yield, and the acid wash process removes substances that restrain the increase in surface area. Therefore, activated carbon with a surface area of 1955 m²/g can be produced after the addition of heat treatment and an acid wash to the process. In addition, the adsorption properties of activated carbon with different heat treatment conditions were studied. Full article

(This article belongs to the Special Issue Biomass Conversion Process and Biorefinery)

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23 pages, 8245 KiB

Open AccessEditor’s ChoiceArticle

Algorithm for Process Innovation by Increasing Ideality

by Vladimir Sojka and Petr Lepsik

Processes 2022, 10(7), 1283; https://doi.org/10.3390/pr10071283 - 29 Jun 2022

Cited by 1 | Viewed by 2207

Abstract

Continual efforts to have better processes lead us to search for new ways to improve and innovate. One of the most powerful approaches to innovating technical systems is the TRIZ (Theory of Inventive Problem Solving). TRIZ is, unfortunately, very hard to learn and [...] Read more.

Continual efforts to have better processes lead us to search for new ways to improve and innovate. One of the most powerful approaches to innovating technical systems is the TRIZ (Theory of Inventive Problem Solving). TRIZ is, unfortunately, very hard to learn and adequately use. This paper introduces a new comprehensive algorithm for the innovation of processes in production based on TRIZ principles. The Algorithm for Process Innovation by Increasing Ideality (AP3I) helps search for innovative ways to improve or change the process—either the whole process or its segments. Besides the original TRIZ, AP3I is easier to use and might be applied by engineers in industrial practice. On the other hand, results from AP3I are probably weaker compared to full TRIZ. Still, the AP3I can be very helpful in efforts to improve processes and can provide powerful ideas. The overall algorithm is also demonstrated in case studies on processes of packing and assembly. Full article

(This article belongs to the Section Process Control and Monitoring)

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18 pages, 4285 KiB

Open AccessEditor’s ChoiceArticle

A Fault-Tolerant and a Reconfigurable Control Framework: Application to a Real Manufacturing System

by Imane Tahiri, Alexandre Philippot, Véronique Carré-Ménétrier and Abdelouahed Tajer

Processes 2022, 10(7), 1266; https://doi.org/10.3390/pr10071266 - 27 Jun 2022

Cited by 5 | Viewed by 1702

Abstract

In this paper, we propose a framework to implement a fault-tolerant and a reconfigurable distributed control approach in programmable logic controller (PLC) for manufacturing systems (MS). The reconfiguration methodology adopted in this paper is based on supervisory control theory (SCT), and it is [...] Read more.

In this paper, we propose a framework to implement a fault-tolerant and a reconfigurable distributed control approach in programmable logic controller (PLC) for manufacturing systems (MS). The reconfiguration methodology adopted in this paper is based on supervisory control theory (SCT), and it is triggered following sensor fault detection. The lost information about these sensors is replaced by timed information allowing the MS to continue its operations. The switch from a normal behavior to a degraded behavior when a sensor fault appears is ensured by reconfiguration rules. The main objective of our framework is to implement the obtained control into a PLC. To meet this objective, the distributed controllers of the two operating modes as well as the reconfiguration rules are interpreted into different Grafcet models. The implementation of these different models is verified by a checker-model technique before being tested on a digital twin and validated on a real MS. Full article

(This article belongs to the Special Issue Modeling, Simulation and Control of Flexible Manufacturing Systems)

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13 pages, 2056 KiB

Open AccessEditor’s ChoiceArticle

Codonopsis laceolata Water Extract Ameliorates Asthma Severity by Inducing Th2 Cells’ and Pulmonary Epithelial Cells’ Apoptosis via NF-κB/COX-2 Pathway

by So-Hyeon Bok, Kang Min Han, Hee-Ock Boo, Seung-Sik Cho and Dae-Hun Park

Processes 2022, 10(7), 1249; https://doi.org/10.3390/pr10071249 - 23 Jun 2022

Cited by 3 | Viewed by 1961

Abstract

Asthma is an incurable pulmonary disease with several symptoms, including abnormal breathing, coughing, and sleep apnea, which can lead to death, and the population of asthma patients has been increasing worldwide. There are many adverse effects in current drugs, and thus, we have [...] Read more.

Asthma is an incurable pulmonary disease with several symptoms, including abnormal breathing, coughing, and sleep apnea, which can lead to death, and the population of asthma patients has been increasing worldwide. There are many adverse effects in current drugs, and thus, we have tried to develop anti-asthmatic agents from natural products such as Codonopsis laceolata. To define the anti-asthmatic effect and the mechanism of Codonopsis laceolata, an animal study was conducted considering different cell counts of BALF, serum IgE levels, morphological changes in the pulmonary system, the Th2 cell transcription factor (GATA-3), and the apoptotic pathway (NF-κB/COX-2). Codonopsis laceolata significantly suppressed the representative asthmatic changes, such as airway remodeling, mucous hypersecretion, epithelial hyperplasia, and inflammatory cell infiltration, in the respiratory system. It suppressed the levels of GATA-3, IL-4, and IL-13. The down-regulation of Th2-related factors, such as GATA-3, IL-4, and IL-13, results from the stimulated apoptosis of Th2 cells and epithelial cells via a decrease in the levels of NF-κB and COX-2. We concluded that Codonopsis laceolata might be a promising anti-asthmatic drug. Full article

(This article belongs to the Special Issue Inhibition and Metabolic Pathway Analysis of Bioactive Substances on Diseases)

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11 pages, 1258 KiB

Open AccessEditor’s ChoiceArticle

Skin-Beautifying Effects of Magnolol and Honokiol Glycosides

by Akiyoshi Sawabe, Ayato Tanaka, Masato Nomura and Ryuji Takeda

Processes 2022, 10(7), 1241; https://doi.org/10.3390/pr10071241 - 22 Jun 2022

Viewed by 2058

Abstract

Glycosides have been synthesized using the starting materials magnolol (1) and honokiol (4), isolated from the Japanese white-bark magnolia, and their anti-aging effects on the skin (skin-beautifying effects) have been examined. The advanced glycation end-product (AGE) inhibitory activity test [...] Read more.

Glycosides have been synthesized using the starting materials magnolol (1) and honokiol (4), isolated from the Japanese white-bark magnolia, and their anti-aging effects on the skin (skin-beautifying effects) have been examined. The advanced glycation end-product (AGE) inhibitory activity test (anti-glycation test) and glycation induction model test, using human-derived dermal fibroblasts, TIG-110 cells, have been conducted to evaluate the anti-aging effects. The synthesized glycoside compounds, 5,5′-di(prop-2-en-1-yl)[1,1′-biphenyl]-2-hydroxy-2′-glucopyranoside (3a), 5,5′-di(prop-2-en-1-yl)[1,1′-biphenyl]-2,2′-diglucopyranoside (3b), 3′,5-di(prop-2-en-1-yl)[1,1′-biphenyl]-4′-hydroxy-2-glucopyranoside (6a) and 3′,5-di(prop-2-en-1-yl)[1,1′-biphenyl]-2,4′-diglucopyranoside (6b), have shown significant anti-glycation activities of less than 0.10 mM in IC50. The glycation induction model test with the fibroblasts, TIG-110 cells, demonstrates that the aforementioned glycosides significantly inhibit the decrease in cell viability. These newly synthesized glycoside compounds are expected to be used as cosmetic ingredients, health foods, and pharmaceutical ingredients, which have inhibitory effects against AGE formation. Full article

(This article belongs to the Special Issue Plants as Functional Food Ingredients and Food Preservative)

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27 pages, 2182 KiB

Open AccessEditor’s ChoiceArticle

Efficient Discrete Element Modeling of Particle Dampers

by Fabio Biondani, Marco Morandini, Gian Luca Ghiringhelli, Mauro Terraneo and Potito Cordisco

Processes 2022, 10(7), 1247; https://doi.org/10.3390/pr10071247 - 22 Jun 2022

Cited by 5 | Viewed by 2729

Abstract

Particle dampers’ dissipative characteristics can be difficult to predict because of their highly non-linear behavior. The application of such devices in deformable vibrating systems can require extensive experimental and numerical analyses; therefore, improving the efficiency when simulating particle dampers would help in this [...] Read more.

Particle dampers’ dissipative characteristics can be difficult to predict because of their highly non-linear behavior. The application of such devices in deformable vibrating systems can require extensive experimental and numerical analyses; therefore, improving the efficiency when simulating particle dampers would help in this regard. Two techniques often proposed to speed up the simulation, namely the adoption of a simplified frictional moment and the reduction of the contact stiffness, are considered; their effect on the simulation run-time, on the ability of the particle bed to sustain shear deformation, and on the prediction of the dissipation performance is investigated for different numerical case studies. The reduction in contact stiffness is studied in relation to the maximum overlap between particles, as well as the contacts’ duration. These numerical simulations are carried out over a wide range of motion regimes, frequencies, and amplitude levels. Experimental results are considered as well. All the simulations are performed using a GPU-based discrete element simulation tool coupled with the multi-body code MBDyn; the results and execution time are compared with those of other solvers. Full article

(This article belongs to the Special Issue DEM Simulations and Modelling of Granular Materials)

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22 pages, 4894 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

A CFD Investigation on the Aerosol Drug Delivery in the Mouth–Throat Airway Using a Pressurized Metered-Dose Inhaler Device

by Farnia Dastoorian, Leila Pakzad, Janusz Kozinski and Ehsan Behzadfar

Processes 2022, 10(7), 1230; https://doi.org/10.3390/pr10071230 - 21 Jun 2022

Cited by 8 | Viewed by 2876

Abstract

Inhalation therapy involving a pressurized metered-dose inhaler (pMDI) is one of the most commonly used and effective treatment methods for patients with asthma. The purpose of this study was to develop a computational fluid dynamics (CFD) model to characterize aerosol flow issued from [...] Read more.

Inhalation therapy involving a pressurized metered-dose inhaler (pMDI) is one of the most commonly used and effective treatment methods for patients with asthma. The purpose of this study was to develop a computational fluid dynamics (CFD) model to characterize aerosol flow issued from a pMDI into a simulated mouth–throat geometry. The effects of air flow rate and cone angle were analyzed in detail. The behaviour of the multiphase flow initiated at the inhaler actuation nozzle and extended through the mouth–throat airway was simulated based on the Eulerian-Lagrangian discrete phase model, with the k-ω model applied for turbulency. We validated our model against published experimental measurements and cover the hydrodynamic aspect of the study. The recirculation we observed at the 90° bend inside the mouth–throat airway resulted in the selective retention of larger diameter particles, and the fluid flow patterns were correlated with drug deposition behaviour. Enhancing air flow rates up to three times reduced the aerodynamic particle diameters to 20%. We also observed that, as cone angle increased, mouth deposition increased; an 8° cone angle was the best angle for the lowest mouth–throat deposition. Full article

(This article belongs to the Special Issue Complex Fluid Dynamics Modeling and Simulation)

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29 pages, 3029 KiB

Open AccessEditor’s ChoiceReview

The Role of Diffusivity in Oil and Gas Industries: Fundamentals, Measurement, and Correlative Techniques

by Ram R. Ratnakar and Birol Dindoruk

Processes 2022, 10(6), 1194; https://doi.org/10.3390/pr10061194 - 15 Jun 2022

Cited by 22 | Viewed by 9528

Abstract

The existence of various native or nonnative species/fluids, along with having more than one phase in the subsurface and within the integrated production and injection systems, generates unique challenges as the pressure, temperature, composition and time (P-T-z and t) domains exhibit multi-scale characteristics. [...] Read more.

The existence of various native or nonnative species/fluids, along with having more than one phase in the subsurface and within the integrated production and injection systems, generates unique challenges as the pressure, temperature, composition and time (P-T-z and t) domains exhibit multi-scale characteristics. In such systems, fluid/component mixing, whether for natural reasons or man-made reasons, is one of the most complex aspects of the behavior of the system, as inherent compositions are partially or all due to these phenomena. Any time a gradient is introduced, these systems try to converge thermodynamically to an equilibrium state while being in the disequilibrium state at scale during the transitional process. These disequilibrium states create diffusive gradients, which, in the absence of flow, control the mixing processes leading to equilibrium at a certain time scale, which could also be a function of various time and length scales associated with the system. Therefore, it is crucial to understand these aspects, especially when technologies that need or utilize these concepts are under development. For example, as the technology of gas-injection-based enhanced oil recovery, CO₂ sequestration and flooding have been developed, deployed and applied to several reservoirs/aquifers worldwide, performing research on mass-transfer mechanisms between gas, oil and aqueous phases became more important, especially in terms of optimal design considerations. It is well-known that in absence of direct frontal contact and convective mixing, diffusive mixing is one of most dominant mass-transfer mechanisms, which has an impact on the effectiveness of the oil recovery and gas injection processes. Therefore, in this work, we review the fundamentals of diffusive mixing processes in general terms and summarize the theoretical, experimental and empirical studies to estimate the diffusion coefficients at high pressure—temperature conditions at various time and length scales relevant to reservoir-fluid systems. Full article

(This article belongs to the Special Issue Gas Diffusivity in Reservoir-Fluid Systems)

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14 pages, 6648 KiB

Open AccessEditor’s ChoiceArticle

Microwave Pre-Treatment of Model Food Waste to Produce Short Chain Organic Acids and Ethanol via Anaerobic Fermentation

by Serena Simonetti, Claudia Fernández Martín and Davide Dionisi

Processes 2022, 10(6), 1176; https://doi.org/10.3390/pr10061176 - 12 Jun 2022

Cited by 2 | Viewed by 2507

Abstract

As an alternative to conventional anaerobic digestion for methane production, anaerobic fermentation (AF) of organic matter can produce short chain organic acids (SCOAs) in a sustainable way. This study investigated the effect of microwave (MW) pre-treatment on the AF of model food waste [...] Read more.

As an alternative to conventional anaerobic digestion for methane production, anaerobic fermentation (AF) of organic matter can produce short chain organic acids (SCOAs) in a sustainable way. This study investigated the effect of microwave (MW) pre-treatment on the AF of model food waste to SCOAs and ethanol. The MW pre-treatment was investigated at three temperatures (120, 150 and 180 °C) and residence times (2, 5 and 8 min). The MW treatment gave a significant reduction in the pH and volatile suspended solids (VSS). The largest reduction in the VSS was 20%, indicating solubilisation of the organic matter. The latter was also confirmed by the increase, although it was not statistically significant, in the soluble chemical oxygen demand (COD) and soluble carbohydrates. In the fermentation batch tests, the total product yield was higher (17.5% COD COD⁻¹) than for the untreated substrate (11.1% COD COD⁻¹). An electricity price of GBP 0.06 kWh⁻¹ would correspond to the market value of the additional SCOAs produced with the pre-treated substrate. Although this price is lower than the current business price of electricity in the UK, the MW pre-treatment could become economically feasible with scale-up effects and by using free excess electricity coming from renewable resources. Full article

(This article belongs to the Section Environmental and Green Processes)

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27 pages, 7656 KiB

Open AccessEditor’s ChoiceReview

Process Analytical Technology for the Production of Parenteral Lipid Emulsions According to Good Manufacturing Practices

by Carsten Grumbach and Peter Czermak

Processes 2022, 10(6), 1174; https://doi.org/10.3390/pr10061174 - 10 Jun 2022

Cited by 3 | Viewed by 6410

Abstract

The good manufacturing practices (GMP) and process analytical technology (PAT) initiatives of the US Food and Drug Administration, in conjunction with International Council for Harmonisation (ICH) quality guidelines Q8, Q9, and Q10, ensure that manufacturing processes for parenteral formulations meet the requirements of [...] Read more.

The good manufacturing practices (GMP) and process analytical technology (PAT) initiatives of the US Food and Drug Administration, in conjunction with International Council for Harmonisation (ICH) quality guidelines Q8, Q9, and Q10, ensure that manufacturing processes for parenteral formulations meet the requirements of increasingly strict regulations. This involves the selection of suitable process analytics for process integration and aseptic processing. In this article, we discuss the PAT requirements for the GMP-compliant manufacturing of parenteral lipid emulsions, which can be used for clinical nutrition or for the delivery of lipophilic active ingredients. There are risks associated with the manufacturing processes, including the potential for unstable emulsions and the formation of large droplets that can induce embolisms in the patient. Parenteral emulsions are currently monitored offline using a statistical approach. Inline analytics, supplemented by measurements of zeta potential, could minimize the above risks. Laser scanning technology, ultrasound attenuation spectroscopy, and photo-optical sensors combined with image analysis may prove to be useful PAT methods. In the future, these technologies could lead to better process understanding and control, thus improving production efficiency. Full article

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19 pages, 1740 KiB

Open AccessEditor’s ChoiceArticle

Numerical Simulation Approach for a Dynamically Operated Sorption-Enhanced Water-Gas Shift Reactor

by Tabea J. Stadler, Jan-Hendrik Knoop, Simon Decker and Peter Pfeifer

Processes 2022, 10(6), 1160; https://doi.org/10.3390/pr10061160 - 9 Jun 2022

Cited by 3 | Viewed by 2543

Abstract

A dynamically operated sorption-enhanced water–gas shift reactor is modelled to leverage its performance by means of model-based process design. This reactor shall provide CO₂-free synthesis gas for e-fuel production from pure CO. The nonlinear model equations describing simultaneous adsorption and reaction [...] Read more.

A dynamically operated sorption-enhanced water–gas shift reactor is modelled to leverage its performance by means of model-based process design. This reactor shall provide CO₂-free synthesis gas for e-fuel production from pure CO. The nonlinear model equations describing simultaneous adsorption and reaction are solved with three numerical approaches in MATLAB: a built-in solver for partial differential equations, a semi-discretization method in combination with an ordinary differential equation solver, and an advanced graphic implementation of the latter method in Simulink. The novel implementation in Simulink offers various advantages for dynamic simulations and is expanded to a process model with six reaction chambers. The continuous conditions in the reaction chambers and the discrete states of the valves, which enable switching between reactive adsorption and regeneration, lead to a hybrid system. Controlling the discrete states in a finite-state machine in Stateflow enables automated switching between reactive adsorption and regeneration depending on predefined conditions, such as a time span or a concentration threshold in the product gas. The established chemical reactor simulation approach features unique possibilities in terms of simulation-driven development of operating procedures for intensified reactor operation. In a base case simulation, the sorbent usage for serial operation with adjusted switching times is increased by almost 15%. Full article

(This article belongs to the Special Issue Numerical Simulation of Nonlinear Dynamical Systems)

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